E. H. ARMSTRONG WAVE SIGNALING SYSTEM Filed June 8, 1922 June Z, 1925.

(241% miNmvroR' Wmfl /fuma ATT RNEY Patented June 2, 1925.

UNITED STATES PATENT DFFICE.

EDWIN H. ARM STRONG, YONKERS, NEW YORK, ASSIGNOR, lBY MESNE ASSIGN- MENTS, TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORA- TION OF PENNSYLVANIA.

WAVE SIGNALING SYSTEM.

Application filed June a, 1922. Serial No. 566,682.

To all whom it may concern:

Be it known that I, EDWIN H. ARM- STRONG, residing at 1032 l/Varburton Avenue, Yonkers, in the county of Westchester, State of New-York, have invented certain new and useful Improvements in \Vave Signaling Systems; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to an electric regenerative system for amplifying varying electric'currents, particularly radio or other high frequency signaling currents, wherein the varying potential of the current to be amplified is impressed on the system, and the relation between the amount of regeneration and the degree of damping of the system is periodically varied to produce transient free oscillations proportional to the amplitude of the impressed potential and wherein the resulting free oscillations and the system are continuously maintained in this transient ordinarily unstable state to obtain super-regenerative amplification or action as described in my co-pending application, Patent No. 1,424,065, Serial No. 480,563 filed June 27, 1921.

The invention has for its object the provision of a method of and apparatus for improving the operation of super-regenerative systems employing vacuum .valves, more particularly for the purpose of obtaining substantial proportionality of the response in the system and for obtaining greater amplification and improved quality of speech when such systems are employed toamplity and receive radio telephone signals or other signals of like character. To this end the characteristics of at least one of the amplifying vacuum valves in the system are modified by inserting resistance in the plate circuit of the valve thru which'the direct cur-' rent of the local battery flows and shunting the resistance by a capacity or a combination of capacity and inductance, which cornbination may betuned to the auxiliary frequency,'wherebythe tendency of the superregenerative-action tobecome irregular and loose its proportionality to the incoming signal is overcome. A further object of the invention contemplates the: extension of this idea to the provision of an electrical filter ofsuch character that it combines the function already described with its natural function of separating speech or signal frequency from the local auxiliary frequency .which serves to periodically vary the relation between the amount of regeneration and the damping of the system.

The particular form of circuit arrangement illustratedin the drawings are prelerrcd embodiments of the invention. By reference to the drawings and to the accompanying description amore complete understanding of the invention may be had. In these drawings :-Fig.'1 illustrates a superregenerative system of the two-tube type with a resistance in the plate circuit of the low or auxiliary frequencyoscillating sys- A theory of operation of this general type of super-regenerative amplifier has been described in my aforementioned patent. This invention, however, is based on thediscovery of the improvement in operation of super-regenerative systems which -is obtained when a resistance of the proper value shunted by appropriate values of capacity and inductance, is inserted in the plate circuit of the Vacuum valve or valves producing the auxiliary frequenc The complete explanation oi the mode 0 operation of the system is highl complicated and is' unnecessa'ry and nee not be considered here because it may be easily demonstrated experimentally. The general idea of the operation of the system will beunderstood, however, from the following explanation :-Referring now to Fig. 1, the source 1 of the varying current to be amplified is associated with a regenerative system comprising the tuned circuit 2, 3, the vacuum valve 4, the feed-back coil 5 and the local battery 6.

The regenerative system should be tuned pending application 566,681 filed concurindicating devices.

, ac'k oscillatin rently herewith. The oscillating system comprises the tuned circuit 7, 8, the valve 9, the inductance 10, the condenser 11 by means of which the oscillations in the system are controlled and maintained at the desired frequency, and the inductance 12. Of course, it is to be understood that other specific forms of oscillating circuit arrangements may be successfully employed. The elements which have been added, and which in combination constitute the basis of this invention, are the resistance 13 which is inserted in the plate circuit of the oscillat .ing valve 9, the inductance 14 and variable condenser 15 connected in series with each other and together shunted across the resistance 13. The condenser 15 and the in- 'ductance 14:.areso tuned and adjusted as to be in resonance with the auxiliary frequenc produced by the vacuum valve 9 in the fee system. The value of the resistance 13 or the ordinary type. tube should be between 10,000 and 20,000 ohms and the ratio of inductance to capacity should be fairly high. As in the usual case, the. received signas are indicated by the telephones 16, which, of course, may be replaced by any of the well known forms of Fig. 2 is substantially similar to 'Fi 1 and ike numerals have been emplo ed to designate corresponding elements of the system. The used the resistance 13 for the double function of im roving the quality of amplification and of filtering the auxiliary currents from the speech frequency currents,

is shown in the oscillating system including the vacuum valve 9. In this arrangement the filter combination comprises two resistances 13 and 13 and the two capacityinductance combinations 14, 15 and 14, 15. It

is to bB'lIIIdBIStOOd, however, that other forms of aperiodic filters comprising a plurahty of recurrent sections of identical or varying values of resistance, inductance and capacity may be employed. The values of resistance and the ratio of inductance to capacity should referabl be as given 'in connection with ig; 1. f course, the values may be altered to take advantage ofthe best practice in the I filter art. The telephones 16 are connected at the end of the filter and complete the path for the continuous currents supplied from the source 17 in the platccircuits of theoscillating valve 9.

It is to be understood that the present inn the conductors of such' signals.

vention is adapted to receive radio-signals, including radio telephone signals, when as sociated with an antenna, loop or other ener collecting, device and to receive wired wire ess signals (so-called wire carrier current transmission) when associated with It should also be understood that modifications may be made in the specific circuit connections above and scope of the invention.

I clalmr 1. An electric regenerative system ada ted to produce super-regenerative action, inc udiing a" feed-back circuit having a certain degree of damping, and means for periodically varyin the relation between the amount of f ced-back and ,the degree of damping of the system comprising, an oscillating system adapted to supply an auxiliary frequency tothe regenerative system, and a .resistance connected in said oscillating system for obtaining substantial proportionality in the response of the system.

2. An electric regenerative system adapted to produce super-regenerative action, including a feed-back ,circuit having a certain degree of dam ing, and means for eriodical- 1y varying t e relation between t e amount of feed-back and the degree of damping of the system comprising,

tem adapted to supp an auxiliary frequency to the regenerative system, and a .0

an oscillating sys- 1y varying-the relation between t e amount of feed-back and the degree of damping of the system comprising, an oscillating system adapted to supply an auxiliary frequency to the regenerative system, a resistance connected in said oscillating system and an inductance and capacity tuned to the auxiliary frequenc connected in shunt with said resistance w ereby substantial proportionality in the response of said system and filtering action for separating out said auxili- 'ary frequency is obtained.

4. Anelectric regenerative syste'm adapted to produce super-regenerative. action, 1ncluding-a feed-back circuit having a certain degree of damping and means for eriodically varying the relation between t e amount .of feed-back and the degree of damping of the system comprising a feed-back oscillating circuit including a vacuum valve havin grid, filament'and plate elements connecte var ing the relation between the amount of fee -back and the degree of damping of the system comprising a feed-back oscillating circuit including a vacuum valve having grid, filament and plate elements connected in their respective circuits, and a resistance connected in the plate circuit of said valve,'

. auxiliary frequency, 'all for the purpose of obtaining substantial proportionality in the response of the system ,and for filtering the auxiliary frequency.

6. An electric regenerative system ada ted to produce super-regenerative actio11,'inc uding a feed-back circuit having a certain degree of damping and means for periodically varying the relation between the amount of feed-back and the degree pf damping ofthe system comprising a feed-back oscillating circuit including a vacuum valve havin grid, filament and plate elements connecte in their respective circuits, and a filter comprising a plurality of resistance, inductance and capacity elements connectedinithe late circuit of said valve, for the pur ose 0 ob- In testimony whereof I afiix my signature.

EDWIN H; ARMSTRONG.

'taining substantial proportionahty in the